I want to write a Python script which downloads every picture of an array which is full of links.
The code looks like this:
for url in array:
if 'jpg' in url or 'jpeg' in url or 'png' in url or 'gif' in url:
print url
As you can see, the if statement is pretty inefficient and I'd like to simplify it. Preferably with a regex if it's possible there. Can someone please help me?
Regex is not the right tool for this because you are not matching patterns, just looking for substrings.
Instead, you should use any and a generator expression:
if any(x in url for x in ('jpg', 'jpeg', 'png', 'gif')):
As a bonus, this solution is lazy like your current one (it only performas as many in membership tests as needed)
Although this is not the same, it is more what you intend to do:
for url in array:
if url.rsplit('.',1)[1] in ('jpg', 'jpeg', 'png', 'gif'):
print url
You may not need regex to do this but if you still want to, here's a way:
http://regex101.com/r/jH8fO4/3 <-- see the regex in action.
^.*\.(jpeg|jpg|png|gif)$
you can of course add more to the end of the expression in order to handle cases where there's a request or variable attached to the url.
edit - updated to comply with the possibility of more than 1 dot in the filename:
http://regex101.com/r/jH8fO4/4 ^[a-z0-9]*\.{1}(jpeg|jpg|png|gif)$
Doing the same thing using regular expressions would look something like this.
pattern = re.compile('jpg|jpeg|png|gif')
for url in array:
if pattern.search(url) is not None:
print url
mygif.com/index.html. Although the original problem will match those urls too, we only want to match the extensions if they're at the end of the url.
I would use os.path.splitext:
import os
for url in array:
_, ext = os.path.splitext(url)
if ext in ('.jpg', '.jpeg', '.png', '.gif'):
print url
